code: def __init__(self, comm, communication_backend_name):
      self.comm = comm
      self.communication_backend_name = communication_backend_name
  
file_path: chainer/chainermn/functions/batch_normalization.py
imports: import chainer
  from chainer.backends import cuda
  from chainer.functions.normalization import batch_normalization
  import chainer.utils
label_desc: Use image node_id 1 to create a new MultiNodeBNImplSelector object  with example: obj = MultiNodeBNImplSelector(comm, communication_backend_name)